The present invention is directed to a solenoid actuated valve device and more particularly to a solenoid actuated valve device for controlling the flow of a fluid in proportion to the electric current applied to the solenoid.
Conventional solenoid actuated valve devices have been proposed which utilize a linear motor of the moveable coil type and a valve means. The linear motor includes a core, a bobbin slidably mounted on the core, a solenoid coil wound on the bobbin, permanent magnets with the magnetic flux of each magnet intersecting the winding of the solenoid coil at right angles and a yoke or body forming a magnetic circuit with the core. The valve means in general includes a sliding valve member which is slidable with the bobbin on the core in response to the electric current flowing through the solenoid coil to thereby proportionally control openings formed in the core between an inlet port and an outlet port.
In such conventional solenoid actuated valve devices, when the solenoid coil receives no electric current, the sliding valve member is always biased by means of a pair of springs in a direction so that the sliding valve member will completely open or completely close the openings to thereby interrupt or fully establish the fluid communication between the inlet and outlet ports. Therefore, in order to cause the sliding valve to move to the full extent in the opposite direction from which it is normally biased, a large magnetic or exciting force must be generated by the application of electric current to the solenoid coil. This usually means that a large amount of electricity consumption is required.
In order to obviate the above-mentioned drawback, the sliding valve member may be balanced by means of a pair of springs which are positioned on opposite sides of the valve member so that the sliding valve member is normally maintained in a standard position when the solenoid coil is de-energized which corresponds approximately to one-half coverage of the openings of elongated configuration. Thus, the sliding valve member can move in the forward direction from the standard position when the electric current is applied in one direction to the solenoid coil while the sliding valve member can move in the rearward direction from the standard position upon the application of electric current in the opposite direction to the solenoid coil. Accordingly, the electricity consumption may be reduced by half. However, the solenoid actuated device may be applied in an idling control system for vehicles and therefore the sliding valve member may deviate from the standard position due to the vibration of the vehicle. This results in uncontrolled fluctuation in the flow of fluid through the openings when the solenoid coil is de-eneregized.